Call number converter for PABX telephone exchange - converts four digit number into binary code using converter and magnetic cores

摘要

The call number converter, for a PABX telephone exchange, converts a four digit call number into a binary code at low cost. The hundreds, tens and units each have four magnetic cores associated with them. The inputs for each group of tens are divided into two subgroups. The subgroups are controlled separately by different first-digits of the selected 3-digit call number.